Niche conservatism determines the occurrence of allopatric populations of Hyla meridionalis in different biogeographical scenarios

Abstract

Niche conservatism controls the distribution of many amphibians during both speciation and invasion processes. In a few species it is possible to investigate the ecological divergence between isolated populations. Hyla meridionalis is an anuran with a distribution pattern of one group of alien populations in southwestern Europe and two allopatric groups of populations in northern Africa that have been diverging for an estimated period of between 2 and 12 million years. In this study we tested the hypothesis that niche conservatism determines the occurrence of a species on two distinct niche scales and in separate geographical regions. Our results indicate that H. meridionalis in some places occupies aquatic habitats that are suboptimal for other anuran species. This fact may have favoured its persistence in this niche and establishment in regions where no equivalent species occur. The two lineages of H. meridionalis overlap extensively in the climate space, even though the western lineage has spread into more marginal niches. Overall, our results support the hypotheses that niche conservatism controls the dispersal and distribution of populations and that a species’ niche can be stable on an evolutionary time scale